Eggshell has three colors: white, blue and brown. Chicken and duck eggs with blue eggshell have superior market for its better appearance, delicious taste, abundant nutrition and higher eggshell thickness and strength compared to those with white eggshell. However, error was often made when breeding blue-eggshell chicken or duck lines based on phenotypes. Studies on the forming and controlling mechanism of eggshell color had important theoretic and practical value. This review mainly discussed the types of eggshell color, its pigment composition and synthesis. Inheritance and heritability, genetic model, the number of genes, and the dominant-recessive relationship between genes for eggshell color were also reviewed. Information described in this review is useful for understanding the forming mechanism of eggshell color.